Device for grinding and clearing drills



I (Mode1.)

D. MEEI-IAN. DEVICE FOR GRINDING AND CLEARING DRILLS.

.No. 282,209. Patented July 31. 1883.

Pmmumu n mm. Washington. D. C

UNITED STATES PATENT OFFICE.

DANIEL MEEHAN, or nnw nnnnonn, MASSACI-IUSETTSf DEVICE FOR GRINDING AND CLEARING DRILLS.

SPECIFICATION forming. part of Letters Patent No. 282,209, dated July 31, 11883;

' Applicationfiledil'une l, 1883. (Modem To all whom it may concern: Be it knownthat I, DANIEL MEEHAN, a citizen of the United States, residing at New Bedford, in the county of Bristol and State of Massachusetts, have invented certain new and useful Improvements in Devices for Holding, Grinding, and Clearing Drills, of which the following is a specification,reference being had therein to the accompanying drawings.

This invention relates to grinding, clearing, and polishing drills, more particularly twistdrills; and it consists of an improved apparatus for holding a drill to anemery or grinding wheel when being ground or cleared, as hereinafter fully described and shown.

In the accompanying drawings, Figure 1 is a perspective view of a drill-holder having my improvements. Fig. 2 is a side elevation. Fig. 3 is a top view. Fig. 4 is a rear. view.

Fig. 5 is a section of hearings or drill-holding plate and sliding plate. 'Fig. 6 is a partial view, showing drill and hearings in section,and illustrating the drill-clearing operation.

A designates the main stock supporting the apparatus. B indicates abed having a standard, a, projecting downward and sliding in a groove with which the stock A is provided. The standard carrying the bed 13 is raised or lowered, as desired, by means of a vertical screw, 1). The bed B is formed with a dovetail groove, in which slides a plate, 0, which carries the bearingscl of the drill to be ground or cleared. The bearings are formed with an opening, f, toreceive an emery or grinding wheel, as indicated at a: in Figs. 2 and 3; A bent tongue or hooked spring, is secured in position, as shown, to be pressed down against the drill, which is passed through the bearings, as indicated at z, and when the drill is drawn the spring tongue enters the spiral groove and causes the drill to rotate, the grinding or clearing being effected at the same time by the emery-wheel. The term clearing is understood to mean the grinding away of the drill in such a manner as to leave the spiral bearing-edge a little more prominent than the other portions, so that in using the drill there is no binding of it.

In Fig. 6 a drill is shown in section in the bearings, the bearing-edge of the drill being marked 1;, and the grinding-wheel being indidrill, as shown, and the drill being drawn through the bearings as the grinding-wheel revolves, the same relative positions of drill and wheel are preserved, and the surface ground forms a spiral track back of the edge '0 and parallel with said edge, a longitudinal clearing of the drill being thus effected. The purpose of such clearing is to prevent the binding of the drill, when in use, by leaving the bearing-edge slightly more prominent than i the surface back of it. The bearings d are provided with a screw, h, which is located at any suitable point along the bearings, so that it may be made to bear against the drill from a direction opposite, or nearly so, to the bearing-point of the tongue 9, the latter usually bearing on the drill from above and the screw h from below, as seen in the drawings. 7

In operation the screw h enters the spiral groove of the drill, and serves as an additional guide in causing a steady rotation of the drill as it is drawn through the bearings, thus cooperating for the purpose with the tongue 9. The said screw also answers the purpose of an adjusting-screw when the bearings are rather larger than required for the drill to be ground, the adjustment being effected by driving the screw farther inward against the drill, and thus practically reducing the space occupied by it. The operator, having placed the drill in the bearings cl, can with one hand press .down the tongue g against the drill, the free A grind ward, is stopped by the gagei closing against the bed B.

, pose set forth.

2. A drill-holding device for grinding and clearing purposes, provided with bearings d, in combination with a tongue, 1 and a screw,

71-, the parts being constructed substantially as shown, for the purposes specified.

3. A drill-holder having adjustable bearings d, with an opening to receive a grindingwheel, an adjusting-screw, h, a spring, g, and gage 'i, in combination with the main stock provided with an adjusting-screw, b, substantially as set forth.

In testimony whereof I afliX my signature in presence of two witnesses.

DANIEL MEEHAN;

Witnesses:

EDWARD T. CHAPIN, VVALTER F. JENNEY. 

